
Effingham County Lake Quality
Illinois, 4 lakes, average grade F (Algae-prone)
Effingham County has 4 monitored lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. 1 of those lake carry an A–F grade. The county-level summary describes that subset, not every water body listed. The county average is F — the most-stressed bracket in our rubric. Most monitored lakes here show persistent nutrient loading and algal pressure.
The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Sara Lake (F); the most-stressed is Sara Lake (F).
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Quick Answers for Effingham County
Planning a trip? Check special fishing regulations for Sara Lake — or check the official Illinois fishing regulations.
All Lakes in Effingham County
4 lakes · 1 graded, 3 not rated1 graded lake · 3 not rated, hidden
| # | Lake | Grade | Clarity | Phosphorus | Algae | Trophic | Access |
|---|---|---|---|---|---|---|---|
| 1 | FSara LakeEffingham | F | 2.2 ft | 59.5 µg/L | 33.9 µg/L | No recent samples | ✓ Public |
| NRAltamont ReservoirEffingham | NR | No recent samples | No recent samples | No recent samples | No recent samples | ✓ Public | |
| NRLake PaulineEffingham | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded | |
| NRLake SaraEffingham | NR | No recent samples | No recent samples | No recent samples | No recent samples | Not recorded |
NR = not rated: there is not enough recent sampling to support a letter. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.
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Other Counties in Illinois
See how Effingham County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all United States (49 states), Canada (Ontario, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs..
Source: EPA National Aquatic Resource Surveys, 2026.